JPH0631569B2 - Stirling engine - Google Patents

Description

The present invention relates to a hybrid Stirling engine having a displacer piston as a free piston.

In the conventional displacer type Stirling engine, either the power piston and the displacer piston are interlocked by using a ring engine, or the displacer piston is completely free to utilize the resonance of the entire system. In the former case, the structure of the crank chamber itself with the built-in link engine is complicated, and it has the drawback of becoming large and costly. In the latter case, it is a low cost and excellent resonance system, so both pistons The difference in the motion phase angle between the two cannot be secured, the efficiency is poor, and the inertial force of the power piston directly contributes to the vibration of the engine.
It has a drawback in that it can be designed only with either a cylinder facing type or a structure of extremely small output which is not so much affected.

In view of such a point, the present invention has an object of a compact and low cost in which the advantages of a so-called link system and a free system in which a free displacer piston is interlocked by using a buffer space fluctuation pressure of a power piston are incorporated. , To provide a novel Stirling engine with high efficiency and low vibration. To achieve this object, the present invention provides a cylinder in which a working gas is enclosed, a displacer piston and a power for reciprocating the inside of the cylinder by an external heating pressure of the working gas to form an expansion space, a compression space and a buffer space. In a Stirling mechanism including a piston and a crankshaft connected to the power piston via a link mechanism, a displacer piston, a power piston having a hollow portion, and a crankshaft are sequentially arranged in a vertical direction, Under the power piston, a crosshead part integrated with the power piston,
A bearing portion slidably supporting the crosshead portion is provided, and a plunger that reciprocates in linkage with the displacer piston is slidably provided in the hollow portion of the power piston, and the crosshead portion and the crank are also provided. The shaft is connected via a connecting rod, and an opening is provided to connect the hollow portion on the crankshaft side defined by the plunger with the buffer space. With this configuration, when the power piston receives the power generated by the expansion and contraction of the working gas and outputs the power to the crankshaft, the working gas is expanded and compressed by applying a fluctuating pressure in the buffer space of the power piston to the plunger. The displacer piston, which works to alternately switch to and, is designed to operate reliably.

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 is a vertical cross-sectional view of a Stirling engine. (1) is a cylinder filled with working gas such as helium, nitrogen, argon, and air, (2) and (3) are interlocked in the cylinder as described later. Reciprocating power piston and displacer piston,
(4) is a heating pipe that communicates with the expansion space (5) above the displacer piston, (6) is a heating wall that is externally heated by the upper burner heat source (7) together with the heating pipe, and (8) is A heat regenerator that communicates with the other end of the heating pipe (4) and contains a porous wire mesh or sintered body, (9) a cooler through which cooling water flows, (10) communicates with the compression space (11) and opens. This is an opening for inflow and outflow of the working gas.

Further, (12) is a plunger connected to the displacer piston (3) via the displacer rod (13), and the displacer piston is formed in the hollow cylindrical portion (14) formed at the center of the power piston (2). It is slidably fitted so as to reciprocate integrally with (3). (15) is the power piston
A crosshead portion integrally formed with (2), (16) is a bearing portion in which the crosshead portion is slidably fitted, and the power piston is provided by an opening (17) formed in the power piston (2).
A buffer space (18) between the bearing (2) and the bearing portion (16) communicates with a hollow portion (14a) on the crankshaft (22) side below the plunger (12). (19) is the power piston
Hollow part above the plunger (12) fixed to the upper surface of (2)
A sealing member for sealing (14b), (20) has a crosshead portion (15) and a crosspin (21) at one end and a crankshaft (22) at the other end opposite to the displacer piston (3). )
And (23) are the rotation paths of the crankshaft (22), (24) are the rod seals, and (25) are the connecting rods.
(26) is a seal ring, (27) is an oil scraping ring for scraping off lubricating oil, (28) is an oil ring, (29) is a crank chamber (30)
Is a shell that forms the.

Next, the operation of the Stirling engine of the present invention will be described with reference to FIG.

I. Isothermal expansion stroke (See (a) in the figure) When the working gas is heated to about 600 ° C by the burner heat source (7) and expansion begins, the pressure is increased by the heating pipe (4), heat regenerator (8), and cooler. It passes through (9) and is applied to the compression space (11) to push down the power piston (2). The internal volume of the buffer space (18) decreases as the power piston (2) descends, and the internal pressure rises. This internal pressure is due to the inertial force of the displacer piston (3), the frictional force generated between the cylinder (1) and the displacer rod (24), the plunger (12) and the hollow portion (14). When the frictional force between the walls begins to be overcome, this pressure is applied to the hollow part (14a) below the plunger (12) through the opening (17) and tries to relatively separate the displacer piston (3) from the power piston (2). To do.

II. Equal volume heat dissipation process (Refer to Figure (b)) Furthermore, the power piston (2) descends and the buffer space (1
As the internal pressure of 8) approaches its maximum, this internal pressure becomes more and more power piston (2) and displacer piston (3).
And the inertial force of the displacer piston (3) acts in the opposite direction of the expansion stroke described above, and doubles the force of separating the pistons (2) and (3). At this time, the various frictional forces described in the expansion stroke act in the blocking direction. Then, when this process approaches the end, the pressure inside the hollow part (14b) surrounded by the plunger (12) and the sealing member (19) becomes higher than the internal pressure of the buffer space (18), and the displacer piston The braking action is started in response to the rise in (3). At this time, the working gas of about 600 ° C that moves to the compression space (11) due to the expansion space (5) gives this heat to the heat regenerator (8), the temperature itself drops to about 200 ° C, and the cooler (9 ) To cool down.

III. Isothermal compression stroke (see (c) in the figure) When the power piston (2) passes through the bottom dead center due to its inertial force, the working gas in the compressed air (11) begins to contract due to cooling, and the power piston (2) At the same time as trying to raise 2), the inertial force starts compression.
Then, when the power piston (2) rises, the internal volume of the buffer space (18) gradually expands and this internal pressure decreases, and conversely the hollow part (1) between the plunger (12) and the sealing member (19).
4b) The difference from the internal pressure becomes decisive and the upward inertial force of the displacer piston (3) becomes extremely small. Then, at the end of this stroke, the inertial force of the displacer piston (3) and the braking action and the various frictional forces mentioned during the expansion stroke are antagonized, at which point the displacer piston (3) is at the top dead center of the cylinder (1). When it reaches, it will be in a stationary state for a moment and will start descending.

IV. Isothermal endothermic stroke (Refer to Fig. 2 (d)) Furthermore, when the power piston (3) rises, the internal pressure of the buffer space (18) becomes minimum and the displacer piston (3) is attracted to the power piston (2). To work. At this time, the various frictional forces and plungers (12) mentioned above
The pressure in the hollow part (14b) between the sealing member (19) and the sealing member (19) acts so as to gradually increase the braking force with respect to the lowering of the displacer piston (3). Then, when the power piston (2) passes through the top dead center, the internal volume of the buffer space (18) begins to decrease in addition to those braking forces, and this time the power piston (2) and the displacer piston (3) are separated. And starts the above-mentioned isothermal expansion process. At this time, the working gas moving from the compression space (11) to the expansion space (5) is endothermicly heated to about 600 ° C. by the heat stored in the heat regenerator (8).

The movement of the power piston (2) which reciprocates by repeating the above four cycles is converted into the rotational movement of the crankshaft (22) by the connecting rod (20) and the output is taken out to the outside.

As described above, the Stirling engine of the present invention has the buffer space (1
Buffer space (18) by slidably fitting the plunger (12) that reciprocates integrally with the displacer piston (3) in the sealed hollow part (14) of the power piston (2) communicating with 8).
Since the fluctuating pressure is used, the displacer piston (3) can be interlocked with high accuracy even though it is free. Moreover, the power piston (2) is connected to the crankshaft (22) with a constant stroke by the link mechanism such as the connecting rod (20), so that the buffer space (18)
It is possible to easily keep the internal fluctuating pressure at a steady value, and adjust the internal volume of the buffer space (18), the internal volume of the sealed hollow part (14b) above the plunger (12), the mass of the displacer piston (3), etc. If optimally selected, performance such as stroke of displacer piston (3) and movement phase angle between both pistons (2) (3)
It is possible to optimally control the factors that directly affect the efficiency.

Also, increasing the ratio of the inertial force of the power piston (2) and the inertial force of the displacer piston (3) (equal to the mass ratio) theoretically increases the motion phase angle (the motion phase angle is 90 It is a requirement to get maximum efficiency by approaching
For this reason, the conventional all-free system uses a power piston.
Although (2) could not be made so light, the hybrid system of the present invention can be designed by adding the inertial mass due to the rotation of the crankshaft (22) to the inertial mass of the power piston (2). ) Itself can be extremely lightweight. Therefore, when the heavy power piston (2) reciprocates up and down, vibration caused by its inertial force is generated by some method (for example, two cylinders facing each other as described above).
In contrast to the all-free system that is transmitted to the outside unless cancelled with, the hybrid system of the present invention balances the inertial force of the power piston (2) with the balance weight of the crankshaft (22) to the outside. It has the feature that vibration transmission can be suppressed to an extremely small level.

Further, in the hybrid Stirling engine according to the present invention, the displacer rod (13) has a power piston compared with the conventional link type displacer type Stirling engine.
Since it does not pass through (2), the crankshaft (22), which is the output shaft, can be arranged almost directly under the cylinder (1), and the displacer rod (13) and crankshaft (22) need not be connected. Therefore, an extremely simple design is possible, and since there is no link mechanism for interlocking the displacer piston (3), there is no power loss caused by this.
It is extremely excellent because of its low cost, high efficiency, small size and light weight.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of the Stirling engine of the present invention, and FIG. 2 is an operation process diagram of the Stirling engine of the present invention. (1) …… Cylinder, (2) …… Power piston (3) …… Displacer piston, (5) …… Expansion space (11) …… Compression space, (12) …… Plunger (14) …… Hollow Part, (18) …… buffer space (22) …… crankshaft

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ryoichi Ueno, Inventor 180 Sakata, Odaizumi-cho, Ora-gun, Gunma Toyosanyo Electric Co., Ltd. (56) Reference JP-A-53-109243 (JP, A) JP 56-619 (JP, B2)

Claims (1)

[Claims] 1. A cylinder containing a working gas, a displacer piston and a power piston that reciprocate in the cylinder by an external heating pressure of the working gas to form an expansion space, a compression space, and a buffer space, and the power piston. In a Stirling engine including a crankshaft connected via a link mechanism, a displacer piston, a power piston having a hollow portion, and a crankshaft are sequentially arranged in a vertical direction, while a power is provided below the power piston. A crosshead portion integrated with the piston and a bearing portion slidably supporting the crosshead portion are provided, and a plunger that reciprocates in linkage with the displacer piston is slidable in the hollow portion of the power piston. And the crosshead portion and the crankshaft Stirling engine linked via a connecting rod, characterized in that an opening for communicating the hollow portion with the buffer space compartmented crankshaft side in this plunger.